Microscopic diffusion anisotropy as a predictor of cognitive decline in asymptomatic adults

Motivation: Conventional diffusion MRI metrics like FA have limitations in assessing WMH lesions due to fiber orientation dispersion. Goal(s): To improve MRI sensitivity to white matter integrity in WMH and assess its clinical relevance in predicting preclinical cognitive decline using advanced diffusion MRI. Approach: FA and μFA maps were acquired in 54 adults using tensor-valued diffusion MRI and their quantitative correlation with cognitive decline were evaluated in WMH lesion and penumbra. Results: While both μFA and FA differentiated WMH from other white matter regions, μFA demonstrated greater sensitivity to predict cognitive decline, suggesting its added specificity to probe white matter integrity in WMH. Impact: Enhanced sensitivity of μFA to subtle white matter integrity and clinical aspect may offer better understanding of underlying histopathological alterations in white WMH, helping earlier detection of cerebrovascular pathology and aiding efforts to identify at-risk individuals and guide timely interventions.